Methods and apparatus for handling or treating particulate material

ABSTRACT

An improved draft tube spout fluid bed (DTSFB) mixing, handling, conveying, and treating apparatus and systems, and methods for operating are provided. The apparatus and systems can accept particulate material and pneumatically or hydraulically conveying the material to mix and/or treat the material. In addition to conveying apparatus, a collection and separation apparatus adapted to receive the conveyed particulate material is also provided. The collection apparatus may include an impaction plate against which the conveyed material is directed to improve mixing and/or treatment. The improved apparatus are characterized by means of controlling the operation of the pneumatic or hydraulic transfer to enhance the mixing and/or reacting by controlling the flow of fluids, for example, air, into and out of the apparatus. The disclosed apparatus may be used to mix particulate material, for example, mortar; react fluids with particulate material; coat particulate material, or simply convey particulate material.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is related to commonly-assigned, U.S. provisionalapplication 60/865,722 filed Nov. 14, 2006 and 60/868,468 filed Dec. 4,2006, the disclosures of which are hereby incorporated by referenceherein.

STATE AND FEDERAL FUNDED RESEARCH

The invention described herein was made with New York State supportunder State Grant Number C010331 from the New York State Department ofTransportation. The State of New York may have certain rights to thisinvention.

The invention described herein was also made with support of theNational Aeronautics and Space Administration (NASA) under Federal GrantNumber NNM05AA04A. The U.S. Government may have certain rights to thisinvention.

TECHNICAL FIELD

This invention relates, generally, to systems, methods, and apparatusfor controlling and handling particulate material, for example, formixing and treating particulate material. More particularly, the presentinvention provides improved draft tube spout fluid bed (DTSFB) materialhandling methods and apparatus having improved controllability andperformance.

BACKGROUND OF THE INVENTION

In many industries, the blending of particulate material, for example,powders is often critical to the performance or desired characteristicsof the resulting product, for example, the blending of powders to makeconcrete, the blending of pharmaceuticals, the blending of foodingredients, or the blending of ceramics, among other products. However,the blending equipment typically used to blend these and otherparticulate materials typically have the disadvantages of producing lackof uniform particle distribution in the product, sensitivity to particlesize, and the excess generation and loss of fine particles (or “fines”)in the product. Aspects of the present invention employ pressurizedfluid flows through conduits, for example, “draft tubes,” to mix, treat,coat, and otherwise handle particulate materials.

One prior art type of particulate mixer is known as a “pneumaticblender.” Pneumatic blenders are similar to fluidized bed mixers in thatthey use air or a gas to agitate the granular or particulate material toproduce a particle mixture. Pneumatic mixers are effective for blendingproducts that do not require uniform particle distribution. For example,pneumatic blenders are typically not used for mixing pharmaceuticalsthat typically require a somewhat uniform particle distribution in theresulting product. Pneumatic blenders are effective for blendingcomponent particles that are similar in size, density, and shape.Pneumatic blenders are, however, highly scalable and can be used toblend particles of vastly differing size and shape. One disadvantage ofpneumatic blenders is that they typically carry off the finer particlesfrom the mixture and, as such, need some form of filtration device, or“bag house,” downstream of the blender to prevent air pollution or lossof product.

Another prior art mixing device is a “convection-type blender.”Convection blenders include ribbon, plow paddle, and conical orbitingscrew mixers, among others. A convention paddle blender is similar tothe type of mixer used for blending ingredients for a cake. Typically,paddle mixers produce high shear in the particulate or powder duringblending. One disadvantage of the paddle blender is that areas ofstagnation can occur where the material fails to mix properly or remainsunmixed, for example, in regions near the wall of the container in whichthe particles are mixed. Other disadvantages of convection mixersinclude the poor blending of mixtures where at least one component isvery dilute. Also, convection blenders are recognized in the art as poorblenders of powders that are very dense or very abrasive. Convectionblenders are also typically difficult to clean, are difficult to scaleup due to their power requirements, provide inconsistent product, andcan be characterized by excessive wear due to abrasion.

Another prior art particulate blending device is the “diffusion-typeblender.” Diffusion blenders operate by allowing the particles to beblended to move with respect to each other by moving the actualcontainment vessel itself. Diffusion blenders are often called “tumbleblenders” because they resemble a container that is tumbled in somefashion. Diffusion blenders can accommodate particles that are vastlydifferent in size, density, and total concentration. These systems areeasily scaled to huge sizes and can be customized to accommodatedifferent types of materials.

Aspects of the present invention overcome many of the disadvantages ofthe prior art blending, mixing, and treating devices while providingimproved blending, mixing, and treatment of particulate material

One industry that can benefit from aspects of the present invention isthe mortar or cement industry. The need to produce roads and bridgeswith concrete structures and surfaces that are stronger, more durable,and less costly to maintain is imperative. To improve the performance ofconcretes in these structures, recent compositions have included fly ashand condensed silica fume. These materials increase the strength ofconcrete, reduce its permeability, and have the potential to decreasecracking through improvements in the paste aggregate bond.

However, most of these fine particles, particularly the silica fume,exist in the form of fine spheres linked together into clusters, ratherthan as isolated spheres [St. John, et al. (1995)]. The performancegains from using materials like silica fume are primarily related to thechemical reaction between calcium hydroxide and the fine material, andsecondarily due to the improved particle packing density resulting fromthe uniform incorporation of finer and finer particles into the mix[Lange, et al. (1997) and Chengzhi, et al. (1996)]. Diamond, et al.(2004) point out that most silica fume used in concrete is in the dry,densified form and consists of agglomerates of sizes between 10 μm andseveral millimeters. Lagerblad, et al. (1995) have reported thatgranulated condensed silica fume is not easily dispersed. Inconventionally mixed concrete, the breakdown of densified silica fumeagglomerates is incomplete and a portion of the agglomerates remains atleast partly intact. Undispersed agglomerates in mortars and concretesresult in poor performance gains due to the inability of the finest sizefraction of the particles to effectively enter the interfacialtransition zone.

Dispersing fine particles in cement is normally achieved in the liquidphase using surfactants known as superplasticizers [Hooton, et al.(1998)]. These admixtures have long been used to help disperse thecementitious powder but the dispersive action occurs only after water isadded and the ‘polymerization’ (hydration and micro-crystallineinterlocking) reactions begin [Anderson, et al. (1988 and Ferraris, etal. (1992)]. Scrivener (1989) reported that despite the use ofsuperplasticizer, some clumps of silica fume are still present and sothe material is not used as efficiently as it could be.

Another approach to providing better dispersion of the agglomerates isto take advantage of the recent advances in dry-phase processingtechniques [Iwasaki, et al. (2001)]. These techniques provide the meansto transform the mechanical properties of the cement by dispersing thepowder uniformly in very small clumps prior to hydration. The additionof fine particles in coarser ones improves the fluidizationcharacteristics of the coarser material [Haberko (1979)] by dispersingfines into the voids between the larger particles and reducing thechanneling and bubbling of the fluidizing gas [Matsumoto, et al.(1986)]. The mixture prevents a cohesive powder such as cement frombehaving as a ‘weak’ solid, held together by chemical and electrostaticforces. Without the addition of the large particles, the powder wouldcrack causing channeling of the gas to take place, rather than aerationand mixing of the particles [Kendall, et al. (2001)].

The inventors surmise that a dry mechanical dispersion of powders shouldlead to a more uniform mixture with smaller clumps of material and wouldserve as a precursor to chemical dispersants, such as superplasticizers,allowing the dispersants to work more effectively, since the diffusionlength required to get to the center of a particle clump will bereduced. Unfortunately, conventional concrete or mortar mixing equipmentcannot provide the intensity of agitation necessary to effectively mixand disperse the finest particles [Ferraris, et al. (2001)]. Thus,obtaining a uniform mixture of these components is generally difficult,inhibiting performance gains and increasing the cost of the materials.Further, the inventors surmise that the dry premixing process, ifexecuted correctly, should be able to produce mortars with propertiescomparable to the best, high-shear rotary mixers, but at much higherthroughputs than are possible with rotary mixers alone.

The “draft tube spout fluid bed” (DTSFB) mixer is also known as aneffective mixing device. Littman (1996) summarized the state ofdevelopment of the DTSFB mixer. U.S. Pat. Nos. 5,248,222 and 5,254,168,both of Littman (one of the co-inventors of the present invention), etal. (the disclosures of which are included by reference herein) discloseadvancements in the particulate mixing art that can be achieved with theDTSFB mixer.

Plawsky, et al. (2003) reported that the dry premixing of sand andcement using a first-generation, DTSFB mixer was more effective as thecement content was reduced and that it might be possible to producecommercially acceptable mortar with lower cement content. However, aconsiderable amount of cement fines passed through the cyclone separatorof Plawsky, et al. (2003) and ended up, unincorporated, in a bag housefilter unit. Due to this loss, the early strength gain of the initialmixtures was slower than the control samples even though the long-termstrengths of the dry, premixed and control samples were comparable. Theinventors now surmise that the loss of fine particles may significantlyaffect mortar performance particularly when ultrafine particles, such asfly ash and silica fume powders, are added to the mixture. In an attemptto avoid the disadvantages of this and other prior art, for example, toinsure more complete incorporation of all materials, the inventorsdesigned, tested, and developed the present invention in its manyaspects.

Aspects of the present invention overcome the above disadvantages andother disadvantages of prior art particulate material blending devices.

SUMMARY OF THE INVENTION

Aspects of the present invention provide methods and apparatus forhandling, treating, and otherwise proceeding particulate material. Forexample, in one aspect, a method and apparatus are provided for blendingpowders using different mechanics than the blending systems discussedabove. Because the mechanical mixing processes are different, it is tobe expected that the resulting blends would possess differentcharacteristics. From an industrial point of view, aspects of theinvention are easily scaled up from very small units to very large unitsin a very predictable manner. Aspects of the invention are based on twomain components, namely, a pneumatic/hydraulic mixing device (which maybe similar to the DTSFB mixer discussed above) and a particle separationand collection device, such as, a “bag house” commonly used for airpollution control and solids recovery. However, the inventors haveimproved on the prior art systems to provide a more advantageous design.The DTSFB has been studied, developed, characterized, and quantified by,for example, as described in U.S. Pat. No. 5,248,222 (the disclosure ofwhich is incorporated by reference herein). Filtering devices, such as,bag houses, are known in the industry.

Aspects of the present invention were first reported by Park, et al,(2005) in which a second generation DTSFB mixer was designed and tested.(The disclosure of Park, et al. (2005) is also included by referenceherein.) The DTSFB disclosed by Park, et al, was found to be morereliable, versatile and easier to operate than the first generationmixer disclosed by Plawsky, et al. (2003). For example, Park, et al.disclosed in their investigation that they were able to reduce theamount of cement in mortars while still producing commerciallyacceptable compressive strengths in mortars as well as higher tensilestrength, determined that the premixing process results in lessshrinkage, and incorporated other cementitious materials, such as, flyash and silica fume to produce a high performance mortar blend. However,only after the submission of Park, et al. for publication did thepresent inventors discover the inherent deficiencies of the devicedisclosed in Park, et al. Specifically, with further investigation, thepresent inventors discovered that in the device disclosed by Park, etal. it is difficult, if not impossible, to control the flow conditionswithin the draft tube. The inventors addressed this limitation in thedevice of Park, et al., as well as the other prior art, with aspects ofthe present invention.

In addition to mixing, aspects of the invention include methods andapparatus for handling and treating (including reacting) particulatematerial. One aspect of the invention is a particulate material handlingapparatus including a vessel having a top and a bottom, the vesseladapted to contain a particulate material; a vertically extendingconduit having an inlet in the vessel and an outlet; a fluid inlet inthe bottom of the vessel, the fluid inlet directed toward the inlet ofthe vertically extending conduit wherein a pressurized fluid introducedthere through produces a flow of at least some of the particulatematerial and fluid through the vertically extending conduit; a fluidoutlet from the vessel; and means for controlling the pressure dropacross the vertically extending conduit to thereby regulate the flow ofthe particulate material through the vertically extending conduit. Theapparatus may further comprise at least one second fluid inlet directedinto the bottom of the vessel. In one aspect, the apparatus comprises aparticulate material reactor, and wherein the fluid inlet introduces afluid reactant that reacts with at least some of the particulatematerial. In one aspect, parameter of the flow of the particulatematerial and fluid though the vertically extending conduit may beparticle flow velocity, fluid flow velocity, solids fraction, voidage,or a combination thereof.

Another aspect is a method for handling particulate material includingintroducing the particulate material to a vessel having a top and abottom, a vertically extending conduit having an inlet in the vessel andan outlet outside of the vessel, a fluid inlet at the bottom directedtoward the inlet of the vertically extending conduit, and a fluidoutlet; introducing a flow of fluid into the fluid inlet and producing aflow of at least some of the particulate material and fluid through thevertically extending conduit; and controlling the pressure drop acrossthe vertically extending conduit to regulate the flow of the particulatematerial through the vertically extending conduit. In one aspect, themethod comprises a particulate material treatment method, and whereinintroducing a flow of fluid into the fluid inlet comprises introducingthe flow of treatment fluid to the inlet, and wherein the method furthercomprises treating at least some of the particulate material with thetreatment fluid. In another aspect, the method comprises a method ofcoating the particulate material, and wherein introducing a flow offluid into the fluid inlet comprises introducing the flow of a fluid tothe inlet adapted to coat the particulate material, and wherein themethod further coating at least some of the particulate material withthe fluid. In another aspect, the coating fluid may be introduced as aspray by means of a nozzle positioned at the outlet of the verticallyextending conduit (that is, at the outlet of the draft tube).

Another aspect of the invention is a method of mixing a firstparticulate material with at least a second particulate material, themethod including introducing the first particulate material and at leastthe second particulate material to a first vessel; pneumatically orhydraulically conveying at least some of the first particulate materialand at least some of the second particulate material from the firstvessel through a conduit to produce a stream of at least some firstparticulate material and at least some second particulate material inthe conduit; discharging the stream from an open end of the conduit, theopen end of the conduit having a central axis; and impacting the streamdischarged from the open end of the conduit against a surface (forexample, an “impaction plate”) in a second vessel to provide a mixturefirst particulate material and second particulate material in the secondvessel, the surface in the second vessel positioned substantiallyperpendicular to the central axis of the open end of the conduit.

A further aspect of the invention is a particulate material mixingdevice including a first vessel adapted to receive a first particulatematerial and at least a second particulate material; at least oneconduit having an open first end and an open second end, the open secondend having a central axis; means for conveying at least some of thefirst particulate material and at least some of the second particulatematerial from the first vessel into the open first end of the conduitand out the open second end of the conduit in a stream of material; asecond vessel positioned to receive the stream of material from the opensecond end of the conduit; and a surface (for example, an “impactionplate”) in the second vessel, the surface oriented substantiallyperpendicular to the central axis of the open second end of the conduitand positioned to receive and deflect the stream of material and providea mixture of the first particulate material and at least the secondparticulate material in the second vessel.

A still further aspect of the invention is a method of manufacturing abinder material for use in fabricating a mortar, the method includingintroducing sand and at least cement to a first vessel; pneumaticallyconveying at least some of the sand and at least some of the cement fromthe first vessel through a conduit to produce a stream of material inthe conduit; discharging the stream from an open end of the conduit, theopen end of the conduit having a central axis; and impacting the streamdischarged from the open end of the conduit against a surface in asecond vessel to provide the binder material comprising the sand and thecement in the second vessel, the surface in the second vessel positionedsubstantially perpendicular to the central axis of the open end of theconduit.

These and other aspects, features, and advantages of this invention willbecome apparent from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE FIGURES

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention will be readily understood from thefollowing detailed description of aspects of the invention taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram, in cross-section, of a particulatematerial handling apparatus according to one aspect of the invention.

FIG. 2 is a detailed schematic diagram of the lower section of theapparatus shown in FIG. 1 as identified by detail 2 in FIG. 1.

FIG. 3 is a schematic diagram, in cross-section, of system having two ormore of the apparatus shown in FIG. 1 operated in conjunction, accordingto an aspect of the invention.

FIG. 4 is a schematic diagram, in cross-section, of another particulatematerial handling apparatus according to an aspect of the invention.

FIG. 5 is a schematic diagram, in cross-section, of vessel to which theapparatuses illustrated in FIGS. 1 and 4 may discharge particulatematerial.

FIG. 6 is a detailed schematic view of the outlet of the tube and impactplate shown in FIG. 5 according to one aspect of the invention.

FIG. 7 is a schematic diagram of a system employing aspects of thepresent invention.

FIG. 8 is a schematic diagram of a particle handling system having aplurality of particulate treatment apparatus feeding a collection vesselaccording to another aspect of the invention.

DETAILED DESCRIPTION OF THE FIGURES

Aspects of the present invention may be utilized to handle and treatparticulate material in a broad range of applications. For example,aspects of the invention may be used for, but are not limited to, mixingparticulate material, treating particulate material, coating particulatematerial, and simply transporting particulate material, among otherhandling and treating that are recognizable by those of skill in theart.

FIG. 1 is a schematic diagram, in cross-section, of a particulatematerial handling apparatus 10 according to one aspect of the invention.Apparatus 10 includes a vessel 12, for example, a circular cylindricalvessel, though any non-circular or non-cylindrical vessel may be used,as appropriate. Vessel 12 includes a closed top 14 and a closed bottom16 and, according to aspects of the invention, contains particulatematerial 18. Particulate material 18 may include any particulatematerial, for example, a powder, pellets, beads, chips, chunks, and thelike, which may be metallic or non-metallic, for example, sand, stone,pharmaceuticals, saw dust, wood chips, food particles, ceramics, porousmaterial, catalysts, catalytic materials, absorbents, adsorbents, ionexchange resins, and the like. In one aspect, particulate material 18may comprise a plurality of particulate materials, for examples,materials intended to be mixed by apparatus 10, for instance, sand andcement. In one aspect, particulate material 18 may comprise a materialhaving sufficient voidage, that is, space between particles, when placedin vessel 12 that a fluid, for example, a gas or liquid, may be passedthrough particulate material 18. Particulate material 18 may form alevel of material 19, below top 14 of vessel 12 whereby a void space 21is provided in top 14 of vessel 12, for example, an annular void space.Void space 21 may provide a plenum into which fluid passes after passingthrough material 18 prior to, for example, exiting vessel 12.

According to aspects of the invention, vessel 12 of apparatus 10includes at least one conduit, pipe, or tube 20 (which may be referredto in the art as a “draft tube”) having an open first end 22 positionedinside vessel 12 and an open second end 24 positioned outside or insideof vessel 12. Conduit 20 may typically be directed vertically withinvessel 12, as shown in FIG. 1; however, conduit 20 may be oriented atany angle, that is, an angle from the vertical, while effecting thefunction described in this specification and attached claims.Optionally, the open second end 24 of conduit 20 may be located in asecond vessel 25 (shown in phantom in FIG. 1). A typical second vessel25 that may be used in aspects of the invention is described anddiscussed with respect to FIG. 5 below, though any vessel which isadapted to collect particulate material may be used. Conduit 20 may haveany convenient cross-section, for example, circular, oval, orrectangular, but is typically circular in cross section. In one aspect,conduit 20 may be directed substantially vertically in vessel 12 wherebyconduit 20 forms an annular region 26 in vessel 12 between the outsideof conduit 20 and the inside of vessel 12.

Vessel 12 includes at least one fluid inlet 28 positioned in the bottom16 of vessel 12 for receiving a fluid 36 (that is, a liquid or gas) andat least one fluid outlet 32 positioned in top 14 of vessel 12. Fluid 36may be a multiphase fluid, for example, a fluid containing a liquid andsolids, a fluid containing a liquid and a gas, a fluid containing a gasand solids, or a fluid containing a liquid, a gas, and solids. It willbe understood by those in the art, that the multiphase fluid may containone or more liquids, one or more gases, or one or more different solidsdepending upon the treatment to be performed in vessel 12. For example,in one aspect, fluid 36 may be a mixture of contaminated water andhydrogen gas that can catalytically treat the water to removecontaminants, such as trichloroethylene. Vessel 12 may also include atleast one inlet 33, for example, positioned in top 14, for instance, forintroducing particulate material 18 to vessel 12. Inlet 28 comprises aconduit having a fluid outlet 30 directed toward inlet 22 of conduit 20.According to aspects of the invention, inlet 28 is so positioned wherebyfluid introduced to inlet 28 and directed toward inlet 22 of conduit 20produces a flow of at least some of particulate material 18 and fluidthrough the conduit 20. Due to the typical expansion of fluid flow asthe fluid leaves inlet 28, the diameter of inlet 28 may be smaller thanthe diameter of inlet 22. Also, the spacing of inlet 28 from inlet 22may be varied, for example, the elevation of inlet 28 may be varied, forinstance, depending upon the nature of the particulate material 18. Aswill be discussed below, in some aspects of the invention, the flow offluid through inlet 28 may be augmented by one or more additional fluidinlets.

According to aspects of the invention, the outlet 32 may include somemeans 34 for regulating or controlling the flow of fluid through outlet32. Outlet 32 may be a conduit and means 34 may be a valve, for example,a ball, a needle, a globe, or gate valve. In aspects of the invention,means 34 controls the flow of fluid from outlet 32 whereby at least oneparameter of the flow of particulate material 18 and fluid though theconduit 20 is varied. For example, varying the flow through outlet 32may vary particle flow velocity, fluid flow velocity, voidage, or acombination of two or more of these parameters. In one aspect of theinvention, vessel 12 may include at least one means 35 for controllingthe pressure drop across conduit 20. Contrary to prior art device, forexample, the device disclosed by Plawsky, et al., by controlling orregulating the pressure drop across conduit 20, aspects of the presentinvention permit the operator to regulate or control the flow of theparticulate material through conduit 20, for example, to control theflow regime in conduit 20 or control the solids fraction of theparticulate material flowing through conduit 20. In FIG. 1, means 35 isillustrated schematically for reference only; however, in aspects of theinvention, a pressure drop across conduit 20 may be controlled by meanof a restriction 21 in conduit 20 or a restriction down stream ofconduit 20, for example, a restriction in optional vessel 25 or arestriction 29 in a conduit 27 leading from vessel 25, such as, a valve.The controlling of the pressure drop across conduit 20 may be practicedby controlling or regulating the pressure in vessel 12, by controllingor regulating the pressure in optional vessel 25, or both. Further meansfor monitoring this pressure drop will be discussed below.

FIG. 2 is a detailed schematic diagram of the lower section of theapparatus 10 shown in FIG. 1 as identified by Detail 2 in FIG. 1.According to aspects of the invention, as a fluid, for example, a gas ora liquid, is introduced to vessel 12 through inlet 28, as indicated byarrow 36, the fluid enters vessel 12 and entrains at least some ofparticulate material 18 into open end 22 of conduit 20, as indicated byarrows 38, and entrains particulate material 18 through conduit 20, asindicated by arrow 40. As described in, for example, U.S. Pat. No.5,248,222, the introduction of a pressurized fluid, typically, air(though other gases or liquids may be used), into inlet 28 (and/or otherinlets as described below) agitates and/or entrains the particulatematerial 18 above inlet 28 whereby particulate material 18 will flowlike a fluid. In one aspect of the invention, this agitation and/oraeration of particulate material is referred to as “fluidization,”whereby a normally solid particulate material 18 is induced to behavesomewhat like a fluid under the influence of the fluid introduced toinlet 28. The fluidization of the particulate material and theconsequent creation of a pressure differential between the open end 22and open end 24 of conduit 20 promotes the flow of the aeratedparticulate material 18 from open end 22, through conduit 20, and out ofopen end 24.

In some aspects of the invention, at least some of the fluid introducedthrough inlet 28 may also pass through particulate material 18 inannulus 26, as indicated by arrows 42, and exit vessel 12 through outlet32. Thus, according to aspects of the invention, apparatus 10 maycomprise an apparatus for handling or transporting particulate material18 through conduit 20; an apparatus for treating particulate material 18with a fluid 36, that is, for treating particulate material 18 inconduit 20, in annulus 26, or a combination thereof; an apparatus formixing one or more particulate materials; or a combination thereof.However, unlike prior art apparatus, apparatus 10 according to aspectsof the present invention, the nature of the flow of material in conduit20 and annulus 26 may be moderated and controlled, for example, bymanipulating the valve 34 in outlet 32 or by manipulating the pressuredrop across conduit 20. As will be discussed further below, the pressuredrop across conduit 20 may be varied in numerous ways according to theinvention, for example, by introducing a restriction to conduit 20; byintroducing a restriction to a down stream flow, for example, by meansof a pressure control element, such as, a valve; or by providing avessel downstream of conduit 20, for example, a vessel in which pressureis regulated. In one aspect of the invention, the concentration of thesolid particles 18 transferred through conduit 20 may be regulatedand/or controlled by regulating and/or controlling the pressure dropacross conduit 20, for example, by manipulating a valve in an outletfrom a downstream vessel.

Apparatus 10 shown in FIGS. 1 and 2, with or without means 35 forcontrolling the pressure drop across conduit 20, may be used to handle,treat, and/or react particulate material 18 or for handling, treating,or reacting fluid 36. For example, apparatus 10 may comprise a mixingapparatus for mixing two or more materials, as will be discussed below.Apparatus 10 may also comprise a treatment apparatus, for example, anapparatus for treating the fluid introduced to inlet 28 with theparticulate material 18, for instance, hydrocarbon cracking, ionexchange, or SO₂ stripping, or for treating the particulate material 18with the fluid introduced to inlet 28, for example, for steam strippingor regeneration of an ion exchange resin. Apparatus 10 shown in FIGS. 1and 2, with or without means 35 for controlling the pressure drop acrossconduit 20, may be used to execute a chemical or physical reaction, forexample, a reaction that particulate material 18 may or may not takepart in, for example, may or may not catalyze, using at least part ofthe fluid streams 36 entering through inlet 28 (or auxiliary inletsdiscussed below). A chemical or physical reaction may take place in theannular region 26, or in conduit 20, or both in region 26 and in conduit20. A reaction may also take place in down stream vessel 25. Particulatematerial 18 may return at least in part through inlet 33 after residencein vessel 25, for example, where a physical or chemical reaction mayhave taken place prior to return through inlet 33, though all thematerial 18 passed to vessel 25 may be returned to vessel 12. Typicalchemical or physical reactions that may be practiced in vessel 12 mayinclude, but are not limited to, catalytic oil cracking, proteinseparations, particle mixing, and particle coating, among others.

According to aspects of the invention, particulate material 18 maycomprise one or more particulate materials, such as sand and cement,that when aerated and transported through conduit 20 are at leastpartially mixed to provide a mixture of particulate material dischargedfrom open end 24 of conduit 20. For example, during transport throughconduit 20, the inventors surmise that the turbulent eddies generated inconduit 20 provide shearing forces that overcome particle surfaceeffects, such as van der Waals forces and electrostatic forces that holdindividual particles in clumps, to break up clusters and clumps ofparticulate material and provide a more uniformly mixed material. Inanother aspect of the invention, apparatus 10 may comprise a coatingapparatus by which the particulate material 18 may be coated with amaterial introduced to inlet 28 or present in annulus 26, whiletransported through conduit 20.

FIG. 3 is a schematic diagram, in cross-section, of a system 100 havingtwo apparatus 110 and 210, which may be similar to apparatus 10 shown inFIG. 1, operated in conjunction according to an aspect of the invention.Similar to the structure and operation of apparatus 10, apparatus 110includes a vessel 112 having a substantially vertical conduit 120, oneor more inlets 128 and 138, one or more outlets 132, one or more inlets133, a control valve 134, and containing particulate material 118.Inlets 138 (and inlets 238 below) may be simply open conduitsdischarging to vessel 112 or may comprise a conduit having a pluralityof holes or orifices adapted to direct fluid 129 away from inlet 128,for example, upward, away from inlet 128. Also similar to the structureand operation of apparatus 10, apparatus 210 includes a vessel 212having a substantially vertical conduit 220, one or more inlets 228 and238, one or more outlets 232, one or more inlets 233, a control valve234, and containing particulate material 218. As is typical of aspectsof the invention, apparatus 110 and 210 may include means forcontrolling the pressure drop across the vertically extending conduits120, 220 to thereby regulate the flow of the particulate materialthrough the vertically extending conduit, for example, control valves134 and 234, respectively. The position of inlets 138 and 238 may varydepending upon the treatment being performed, but inlets 138 and 238 aretypically positioned toward the bottom of vessels 112 and 212,respectively. In the aspect of the invention shown, conduit 120 ofapparatus 110 is in fluid communication with inlet 233 of apparatus 220,for example, via conduit 150. Also, conduit 220 of apparatus 210 is influid communication with inlet 133 of apparatus 120, for example, viaconduit 160. According to one aspect of the invention, system 100 maycomprise a chemical treatment or processing system, for example, acounter-current chemical treatment or processing system.

In one aspect, the flow of fluid 139 and 239 in FIG. 3 (and of fluid 36in FIG. 1) may be adapted to fluidize particulate material 118 and 218(and 18), respectively, residing in the annular region between conduits120 and 220 (and 20) and the inside diameter of vessels 112 and 212 (and12), respectively, whereby either particulate fluidization or aggregatefluidization occurs. As is known in the art, particulate fluidization ischaracterized by bed expansion while aggregate fluidization ischaracterized by bubbling.

With reference to FIG. 3, a fluid 129 (for example, a liquid, a gas, ora multiphase fluid) may be introduced to inlets 138 and be passedthrough particulate material 118, for example, while treatingparticulate material 118 or being treated by particulate material 118,and then passed out of outlet 132. At essentially the same time,particulate material 118 flows toward the inlet of conduit 120 and isentrained by fluid 139 introduced via inlet 128 and transferred throughconduit 120, through conduit 150 to inlet 233 of vessel 212. Also, forexample, at substantially the same time, a similar process is beingperformed in apparatus 210. Specifically, a fluid 229 (for example, aliquid, a gas, or a multiphase fluid) may be introduced to inlets 238 ofvessel 212 and passed through particulate material 218, for example,while treating particulate material 218 or being treated by particulatematerial 218, and then passed out of outlet 232. At essentially the sametime, particulate material 218 flows toward the inlet of conduit 220 andis entrained by fluid 239 introduced via inlet 228 and transferredthrough conduit 220, through conduit 160 to inlet 133 of vessel 112. Asshown in FIG. 3, inlets 133 may include a baffle plate 135, 235,respectively, to deflect the incoming particulate material to moregenerally distribute the material more evenly in the respective vessels.As a result, in one aspect, a counter-current flow of material 118 andfluid 129 is provided in vessel 112, for example, wherein material 118flows downward and fluid 129 flows upward, and a counter-current flow ofmaterial 218 and fluid 229 is provided in vessel 212, for example,wherein material 218 flows downward and fluid 229 flows upward.According to aspects of the invention, various chemical treatments maybe practiced effectively in system 100. One or more subsequentapparatus, 10, 110, 120, may also be provided upstream of apparatus 110or downstream of apparatus 210.

In one aspect, particulate material 118 and 218 may be replenished, forexample, continuously, whereby a level 119 and 219 of material 118 and218, respectively, is substantially maintained in vessels 112 and 212during treatment. In another aspect, materials 118 and 218 may not bereplenished whereby levels 119 and 219 may drop in elevation duringtreatment.

In one aspect, system 100 may include one or more fluid particleseparating devices 170, shown in phantom in FIG. 3, adapted to separateparticulate material from liquid or gas while the material and fluid arebeing conveyed between vessels 112 and 212. For example, as shown inFIG. 3, instead of passing through conduit 150, the particulate materialand fluid discharged from draft tube 120 may be passed through conduit250 to separating device 170 to, for example, limit the amount of fluidforwarded to vessel 212. Separating device 170 may be any device adaptedto isolated particulate material from a liquid or gas, for example,separating device 170 may be a screening device having a screeningmedium, a settling chamber, a hydrocyclone, a charged surface (forcollecting charged particles), an electric field or magnet, or any otherconventional device adapted to isolate the particles flowing betweenvessel 112 and vessel 212. As shown in FIG. 3, separating device 170 mayreceive a flow of particulate material from conduit 250, isolate atleast some of the particulate material, and forward the separatedparticulate material, possibly with some fluid, to conduit 252 and thento inlet 233 of vessel 212. Conduit 252 may include a flow controldevice 254, for example, a knife gate valve, to regulate the flow ofparticle material to vessel 212. The fluid separated by separationdevice 170 may be passed through conduit 172 for further treatment,re-use, or disposal. In one aspect, the separated fluid in conduit 172may be returned for reintroduction through conduits 128, 138, 228, or238, if desired, for example, after treatment. Conduit 172 may typicallyinclude a pressure-regulating device 174 adapted to regulate thepressure of the fluid discharged from separating device 170. Similarly,a separating device 170 may also be positioned in conduit 160 to treatthe fluid and particulate material passing from vessel 212 to vessel112. In one aspect, separating device 170 may be positioned in vessel112 and/or vessel 212.

In one aspect of the invention, system 100 may be used for chemicalextraction or concentration, for example, the extraction andconcentration of metals from mine tailings, or the extraction ofundesirable components, such as, heavy metals from waste water streams,and the like. For example, system 100 may be used to extract orconcentrate a metal from a metal-laden stream. Specifically, system 100may be used to extract copper from a copper-laden stream, for example,by varying the pH in vessels 112 and 212. Vessel 112 may be filled withresin beads, having an affinity for copper, to an elevation 119. Acopper laden stream (for example, containing Cu⁺⁺ ions) may beintroduced to one or more inlets 138 as fluid 129 (the stream may arelatively low concentration of copper and include other metals andnon-metals) and pass upward through resin beads 118, for example,ion-exchange resin beads. The Cu⁺⁺ laden stream 129 may be introduced ata first pH, for example, a pH greater than 6. As the copper-laden fluid129 encounters the resin beads 118, the Cu⁺⁺ deposits on the beads in aconventional manner. As the fluid 129 continues to flow upward throughthe resin 118, the Cu⁺⁺ in fluid 129 is depleted while the concentrationof Cu⁺⁺ on the resin increases. According to aspects of the invention,while fluid 129 flows upward, resin beads 118 flow downward toward theinlet of conduit 120. As a result, the concentration of the Cu⁺⁺ influid 129 is least at level 119 and the concentration of Cu⁺⁺ on theresin beads 118 is greatest at or near the inlet of conduit 120.According to this aspect of the invention, the Cu⁺⁺ depleted fluid 129may be discharged from outlet 132 and forwarded to storage, reuse, orfurther treatment, for example, to a similar apparatus 100 forextraction of another metal or non-metal.

Typically, at substantially the same time, the Cu⁺⁺ enriched beads 118may be transferred by fluid 139 via conduit 120 through conduit 150 andinlet 233 of vessel 212. Fluid 139 may further treat Cu⁺⁺-laden resinbeads 118, for example, by comprising a second pH, for example,different from the first pH, typically, less than a pH of 8. Fluid 139may also simply be water, wherein little or no reactions take place inconduits 120 and 150.

The treatment practiced in vessel 212 may strip the copper from theresin beads producing a concentrated copper stream and refurbished resinbeads, with little or no copper, that can be returned to vessel 112 forre-use. According to this aspect, an acidic fluid, for example, having apH less than 7, but typically 6 or less, may be introduced to inlets 238of apparatus 210 as fluid 229. In a flow pattern similar that practicedin vessel 112, the Cu⁺⁺ laden resin beads introduced to inlet 233 becomeparticulate material 218 flowing downward in vessel 212 toward the inletof conduit 220. As the Cu⁺⁺-laden beads flow downward, the acidic fluid229 flows upward stripping the Cu⁺⁺ from the resin 218. As a result, dueto this counter-current treatment in vessel 212, the concentration ofthe Cu⁺⁺ in fluid 229 is greatest at level 219 and the concentration ofCu⁺⁺ on the resin beads 118 is least at or near the inlet of conduit220, where they can be transferred through conduit 220 by fluid 239introduced via inlet 228. According to this aspect of the invention, theCu⁺⁺ rich fluid 229 may be discharged from outlet 232 and forwarded tostorage, reuse, or further treatment. Resin beads 218, having little orno Cu⁺⁺, may be returned to vessel 112 via conduits 220 and 160 andinlet 133. Again, Fluid 139 may further treat the Cu⁺⁺-depleted resinbeads 218, or fluid 139 may simply be water, wherein little or noreactions take place in conduits 220 and 160. According to this aspectof the invention, metals and non-metals may be recovered or concentratedas desired by varying the conditions, for example, pH, temperature,and/or pressure within vessels 112 and 212.

In another aspect of the invention, system 100 may be used for treatingfluid 129 with a catalyst or reagent, for example, fluid 129 maycomprise a fluid hydrocarbon, such as a high-molecular-weight oil, andparticles 118 may comprise a catalyst, for example, a zeolite-basedcatalyst. As the hydrocarbon fluid 129 passes through the catalystparticles 118, the catalyst particles 118 may become coked, poisoned,spent, or otherwise deactivated, rendering the catalyst no longercapable of reacting with, that is, catalyzing, fluid 129. Thisdeactivation of particles 118 reduces their catalytic activity andselectivity or inhibits some reagent from reacting with a component offluid 129. When the deactivated particulate material 118, for example,the spent catalyst, reaches the bottom of vessel 112, the spent catalyst118 may be entrained with fluid 139 and passed through conduits 120 and150 to vessel 212 and treated and recovered, for example, stripped ofthe residual hydrocarbons, coke, or other deactivating agent(s) and thenregenerated, for example, with an oxygen-containing gas as fluid 229 invessel 212, such as, air or another appropriate agent that removes orreverses at least some of the deactivating agents or conditions from theparticulate material 218. The regenerated or reactivated catalyst orreagent may then be transferred from vessel 212 via conduits 220 and 160and reintroduced to vessel 112, for example, via inlet 133, for furthertreatment participation in the reaction occurring in vessel 112.Similarly, system 100 may be used to perform hydrocracking and steamreforming of hydrocarbon fluids. System 100 of FIG. 3 may provideenhanced treatment or reacting of reagents since the flow regimes invessels 112 and 212 are typically counter-current. As a result, thereagents or precursors 129, 229 introduced via conduits 138, 238 flowaway from and are typically isolated from the reagents or precursors139, 239 introduced via conduits 128, 228.

In another aspect of the invention, apparatus 100 shown in FIG. 3 mayalso be used for biochemical processing, for example, proteinprocessing, for instance, protein separation or protein purification. Inthis aspect of the invention, a solution containing one or more proteinsor molecules of interest, for example, with or without lysed cell ortissue fragments and with or without biological, organic, or inorganicmolecular components, may be introduced as fluid 129 into inlet 138.Particulate material 118 may comprise beads or pellets having theability to absorb or adsorb the protein or molecule of interest fromfluid 129 under conditions produced by the contact between fluid 129 andthe particle, bead, or pellet 118. Fluid 139 entering inlet 128 entrainsat least some of the particulate material 118 upward through conduit 120and deposits the particulate material 118 either directly or indirectlyinto vessel 212. The material 118 deposited into vessel 212 is nowdesignated particulate material 218. Particulate material 218 movesdownward through vessel 212 as in other aspects of the invention. Fluid229 entering one or more inlets 238 produces an environment withinvessel 212 when it comes in contact with particulate material 218 suchthat particulate material 218 relinquishes the molecular species intofluid 229 which then exits through outlet 232. The fluid discharged fromoutlet 232 may or may not proceed to another downstream process,storage, or disposal.

According to this aspect of the invention, fluid 239 entering inlet 228entrains particulate material 218 through conduit 220 and 160 anddeposits the particulate material 218 either directly or indirectly intovessel 112 via inlet 133, where the process in vessel 112 is allowed tocontinue to proceed. In one aspect, the pH of the fluid 129 in vessel112 may comprise a fluid that causes some molecular species to adhere toan ion exchange resin, and the pH of fluid 229 in vessel 212 may promotethe desorption of the molecular species from the ion exchange resin andso regenerate particulate material 218 for return and continuedprocessing in vessel 112. This biochemical treatment may be practiced atabout room temperature, for example, between about 60 and 75 degrees F.and at a pH ranging from 3 to 11.

In another aspect of the invention, apparatus 10 shown in FIG. 1 mayalso be used for coating particles, for example, coating aerogelparticles or coating pharmaceuticals. For example, the particulatematerial 18 may comprise at least two components: particles to be coatedand the coating material, for example, a powder. The particle velocityand solids volume fraction in conduit 20 (that is, the draft tube) canbe independently specified and controlled, for example, controlledsimultaneously, to provide a more uniform particle coating. As a result,the coating time per pass through the conduit 20 and the environment inwhich the coating takes place can be selected by the user. In oneaspect, apparatus 10 may be used to effectively coat very light aerogelparticles (for example, having a density of about 140 kg/m³) with, forexample, an alcohol, such as, a polyvinyl alcohol (for instance, apolyvinyl alcohol provided by Colorcon Inc. or its equivalent), apolymethymethacrylate (for instance, a polymethymethacrylate provided byDegussa), or a polyurethane to provide a material having improvedthermal insulating properties. These aerogel particles are typicallydifficult to coat using prior art coating devices because of the lowdensity of aerogel particles.

FIG. 4 is a schematic diagram, partially in cross-section, of aparticulate handling apparatus 300 according to one aspect of theinvention. Apparatus 300 shown in FIG. 4 is similar to the apparatusdescribed in U.S. Pat. Nos. 5,254,168, and 5,248,222 of Littman, et al.;however, according to aspects of the present invention, apparatus 300includes improvements over the feeders disclosed in U.S. Pat. Nos.5,254,168, and 5,248,222.

Similar to apparatus 10, 110, and 210, apparatus 300 includes a vessel312, having a closed top 314, a closed bottom 316, and containsparticulate material 318 having a level 319, for example, one or more ofthe particulate materials 18 described above. Vessel 312 of apparatus300 includes at least one conduit 320 having an open first end 322positioned inside vessel 312 and an open second end 324 positionedoutside of vessel 312. Conduit 320 may be similar to and oriented inmanner similar to conduit 20 discussed above. The open second end 324 ofconduit 320 may be located in a second vessel (not shown in FIG. 4), forexample, apparatus 400 shown in FIG. 5. Vessel 312 also includes atleast one fluid inlet 328 positioned in the bottom 316 of vessel 132having an outlet 335, and at least one fluid outlet 332 positioned inthe top of vessel 312 having a valve 334. Valve 334 may be adapted toregulate the flow from and/or pressure within vessel 312 or to regulatethe flow of particulate material out of conduit 320. As is typical ofaspects of the invention, inlet 328 is directed toward inlet 322 ofconduit 320 whereby fluid introduced to inlet 328 and directed towardinlet 322 produces a flow of at least some particulate material 318 andfluid through the conduit 320. As shown in FIG. 4, the outlet 335 ofinlet 328 may be spaced from inlet 322 a distance L_(t) represented byarrows 321.

Vessel 312 of apparatus 300, similar to vessels 12, 112, and 212disclosed above, may typically be sealed vessels. For example, theclosed top 314 of vessel 312 may be sealed by conventional means, forexample, by means of mechanical fasteners or welding. Closed top 314 maybe removably mounted to vessel 312 or include a removal access cover(such as a manhole) to permit access to vessel 312, for example, forintroducing or removing particulate material or for servicing.

As shown in FIG. 4, vessel 312 may typically include at least one outlet332 which includes some means 334, for example, a valve, for regulatingor controlling the flow of fluid through outlet 332. Vessel 312 may alsoinclude an inlet 333, for example, for introducing particulate material318 to vessel 312, for instance, prior to initial processing or forrepeat processing of the particulate material. Inlet 333 may include anisolation device, for example, a valve, and may be provided with a“quick disconnect” to permit access to the inside of vessel 312, forexample, for material removal.

As in the previous aspects of the invention, means 334 is provided toregulate or control the flow of fluid from outlet 332 whereby at leastone parameter of the flow of particulate material 318 and fluid thoughthe conduit 320 may be varied.

As shown in FIG. 4, vessel 312 may comprise a vessel of varyinggeometry. For example, vessel 312 may include an upper or top section313, a middle section 315, and a lower or bottom section 317. Uppersection 313 may comprise a convergent section, for example, a conicalconvergent section comprising an inverted frusto-conical section havingclosed top 340, an open bottom 342, and sloping sides 344. Middlesection 315 may also be convergent similar to section 313 (for example,having sides with a different angle of convergence than section 313),but may also comprise a circular cylindrical section having an open topmounted to open bottom 342 of section 313, and an open bottom 346. Lowersection 317 may also comprise a convergent section, for example, aconical convergent section comprising an inverted frusto-conicalsection, similar to upper section 313, having an open top mounted toopen bottom 346 of section 315, and closed bottom 316, and slopingsides. However, in the aspect shown in FIG. 4, bottom section 317compresses a circular cylindrical section having an open top mounted toopen bottom 346 of middle section 315 and a closed bottom 316. As shown,bottom section 317 may comprise a conical head 348 or may include aninsert 348 having an open top mounted to the open bottom 346 of middlesection 315, a closed bottom 354, and convergent or conical sides 350forming an annular cavity 352 between the circular cylindrical sectionof 317 and the conical sides 350. Side walls 350 may include one or moreperforations, orifices, or inlets that provide fluid communicationbetween annular cavity 352 and the inside of lower section 317. In oneaspect of the invention, vessel 312 may include at least one pressuredetector 360 to provide a pressure indication in vessel 312, and morespecifically, a pressure indicative of the pressure at the inlet 322 ofconduit 320 to be used in providing an indication of the pressure dropacross conduit 320. The detected pressure signal may be forwarded tocontrol system, for example, control system 580 shown in FIG. 7.Pressure indicator 360 may be located anywhere in vessel 312, butpreferably is located as close to inlet 322 as possible.

As shown in FIG. 4, fluid inlet 328 may penetrate the closed bottom 354of convergent head or insert 348, for example, at or near the apex ofthe convergent head or insert 348, and direct fluid toward open inlet322 of conduit 320. In addition, apparatus 300 may include one or moreinlets 330 directed through the side wall of lower section 317 toaugment or replace the fluid provided by inlet 328. The fluid flowintroduced through the one or more inlets 330 may primarily aerate theparticulate material in the annulus outside of conduit 320 and inside ofvessel 312. The fluid provided by the one or more inlets 330 may be thesame fluid or a different fluid from that introduced to inlet 328. Inone aspect, inlets 330 comprise conduits that penetrate the conicalsides 350 of head or insert 348 (for example, when sides 350 are notperforated) or conduits 330 may terminate within annular cavity 352 andsupply fluid to the one or more perforations in conical sides 350 ofconvergent insert 348.

FIG. 5 is a schematic diagram, in cross-section, of an apparatus 400into which the apparatus 10, 100, and 300 illustrated in FIGS. 1 and 4may discharge particulate material. Apparatus 400 includes a vessel 412having an inlet conduit 414 for particulate material and fluid, anoutlet conduit 416 for primarily fluid, for example, a gas, such as air,and a particulate material outlet conduit 418, which may discharge afluid, such as water. Inlet conduit 414 includes an open first end 413and an open second end 415. Outlet conduit 418 may typically include avalve 419, for example, an isolation knife gate valve. As shown in FIG.5, vessel 412 may be multiple sections, for example, an upper or topsection 413 comprising a cylindrical vessel, for example, a circularcylindrical vessel, having closed top 420 and an open bottom 422. Vessel412 may also include a lower or bottom section 417 having an open topmounted or connected to open bottom 422 of section 413 and asubstantially closed bottom 424. As shown, bottom section 417 maycomprises a downwardly converging bottom section, for example, having aninverted frusto-conical shape. The frusto-conical shape of section 417may have an axis concentric with the axis of upper section 413, or, asshown, may have an axis that is off set from the axis of upper section413, for example, whereby section 417 converges to outlet 418 to oneside of apparatus 400.

According to aspects of the invention, apparatus 400 receives a streamof particulate material and fluid, for example, air or water, via inlet414, as indicated by arrow 426 (for example, from one of conduits 20,120, 220, or 320 described above). In one aspect, inlet conduit 414comprises the upper end of one of conduits 20, 120, 220, or 320described above. In one aspect, inlet conduit 414 may be a separateconduit from the above-referenced conduits, for example, apparatus 400may be distal from the apparatus 10, 100, and 200 described above andcommunicate with those apparatus by means of one or more conduits.

In one aspect of the invention, vessel 412 may include at least onepressure detector 460 to provide a pressure indication in vessel 412,and more specifically, a pressure indicative of the pressure at theoutlet 415 of conduit 414 to be used in providing an indication of thepressure drop across conduit 414. The detected pressure signal may beforwarded to control system, for example, control system 580 shown inFIG. 7. Pressure indicator 460 may be located anywhere in vessel 412,but preferably is located as close to outlet 415 as possible. As shownin FIG. 5, in one aspect, outlet conduit 416 includes apressure-regulating device 470, for example, a control valve. Pressureregulating device 470 provides a means for regulating and controllingthe pressure in vessel 412. As shown, a pressure indicator 460 may belocated upstream of device 470 as shown. According to aspects of theinvention, by regulating and controlling the pressure in vessel 412, andthus the pressure at the outlet 415 of conduit 414, with knowledge ofthe pressure at the inlet of conduit 414, the pressure drop acrossconduit 414 may be regulated and controlled. The regulating and controlof this pressure drop allows the operator to regulate and control theflow regime (for example, dense or dilute phase flow) through conduit414, as well as, the solids flow rate and the solids fraction flowingthrough conduit 414.

In one aspect, apparatus 400 functions as a separation device for theparticulate material and fluid introduced to inlet conduit 414. Forexample, in one aspect, the particulate material, for example,particulate material 18 described above, introduced to inlet conduit 414is discharged from second end 415 whereby at least some, typically,most, of the particulate material settles in the closed bottom 424 oflower section 417 of vessel 412, as indicated by material level 428, andthe fluid, typically, air, is discharged from outlet conduit 416. In oneaspect of the invention, apparatus 400 includes means to enhance thisparticle-fluid separation.

As shown in FIG. 5, inlet conduit 414 typically penetrates bottomsection 417 and terminates in vessel 412 at second end 415. According toaspects of the invention, conduit 414 may terminate at a locationadjacent to a plate 444 mounted in vessel 412 whereby the dischargedparticulate material and fluid from conduit 414 impacts plate 444. Theimpact of material on plate 444 may typically be a turbulent impactwhereby clumps of particulate material, if present, are disrupted (thatis, according to aspects of the invention, plate 444 may be referred toas an “impaction plate”) and the particulate material may be deflectedtoward the closed bottom 424 as indicated by arrows 430. At the sametime, the impact of the stream of particulate material and fluid againstplate 444 further promotes intermingling or mixing of the particulatematerial, that is, above the mixing that occurs in conduits 20, 120,220, 320, and/or 414. After impact, the particulate material typicallycollects under the force of gravity in the bottom chamber section 417 asindicated by material level (or pile) 428. The particulate material maybe recycled to vessel 412 or to another vessel, such as, vessel 312 inFIG. 4, through conduit 418 and valve 419.

As shown in FIG. 5, impaction plate 444 may be a hemispherically-shapedsurface that directs the particulate material toward the closed bottom424 of vessel 412. However, in one aspect, impaction plate 444 may beany surface in vessel 412 upon which the stream of particulate materialand fluid may be directed whereby at least some of the clumps ofparticulate material, if present, are disrupted and commingling ormixing of the individual particulate materials is promoted or enhanced.In one aspect, the impact of particulate material on impaction plate 444may also disrupt particulate clusters or clumps whereby the presence ofparticle clusters or clumps in the particulate material is reduced oreliminated. Further details of impaction plate 444 are illustrated anddescribed with respect to FIG. 6 below.

In contrast to the prior art system disclosed by Plawsky, et al. (2003),where the draft tube directs the particulate material to a cyclone-typeseparator to remove gas and fine particulate from the particulate streamand little or no mixing or cluster disruption is provided, in aspects ofthe present invention, the impaction plate 444 may typically turbulentlyor violently disrupt the flow of particulate material discharged frominlet conduit 414 or conduits 20, 120, 220, and 320 to promote furthermixing of the particulate material and the elimination of particleclusters and clumps.

Impaction plate 444 may be suspended or mounted anywhere within vessel412 by conventional means. As shown in FIG. 5, impaction plate 444 maybe mounted by a mounting rod 446 suspended from the closed top 420 ofvessel 412. As also shown in FIG. 5, impaction plate 444 and mountingrod 446 may be mounted within conduit 448, which may also be suspendedfrom closed top 420, though in one aspect, conduit 448 may be omitted.According to other aspects of the invention, impaction plate 444 may bymounted by means of one or more support arms (not shown) projecting fromthe internal walls of vessel 412, mounted directly to the internal wallsof vessel 412, or comprise a surface of the internal walls of vessel412, among other mounting arrangements.

Depending upon the material being treated, for example, coated,impaction plate 444 may be omitted. For instance, impaction againstplate 444 may be undesirable for delicate particulate materials, suchas, pharmaceutical pills, candy, or a coated particle, which could bedamaged upon impaction. In one aspect, impaction plate 444 may bereplaced with a downward moving fluid stream that may provide a moregentle means of commingling the particulate material or prevent damage.

In one aspect of the invention, where apparatus 400 shown in FIG. 5 mayalso be used to coat particles, for example, aerogel particles, thecoating fluid may be introduced, for example, in heated air, at theoutlet 415 of conduit 414. For example, the coating fluid may beintroduced by means of a nozzle in a fine spray, for example, a finespray of one of the coating fluids mentioned herein, such as provided byColorcon. A typical nozzle location is shown schematically as nozzle 465in FIG. 5. Coating nozzle 465, shown in phantom, may be used with orwithout impaction plate 444. In one aspect, impaction plate 444 isomitted and coating nozzle 465 may be centrally located above outlet415. In addition or in lieu of providing heated air, to aid in thedrying of the coating on the particles, a heating device may also beprovided in the path of the particles after they are coated, forexample, a heating ring as shown by ring 467 shown in phantom in FIG. 5.

FIG. 6 is a detailed schematic view of the second open end 415 of inletconduit 414 and impact plate 444 shown in FIG. 5 according to one aspectof the invention. As shown in FIG. 6, impaction plate 444 may compriseany substantially flat or curved plate positioned to receive a flow ofparticulate material and fluid discharged from conduit 414. Impactionplate 444 may have a normal 445 at the point or vicinity of impact ofthe particulate material that makes an angle Θ, with the axis 435 ofconduit 414. In one aspect, the angle Θ may range from about 0 degrees(that is, the point of impact on plate 444 may be substantiallyperpendicular to the axis of conduit 414) to an angle of about 60degrees, but Θ typically may range from about 0 degrees to about 30degrees. The normal 445 of impaction plate 444 may be coaxial with thecenterline 435 of conduit 414; however, these centerlines may also beoffset from each other, as shown in FIG. 6, for example, due tofabrication tolerances or as desired.

While the particulate material typically settles in the bottom of vessel412, as indicated by level or pile 428, the fluid (typically, gas,though the fluid may be a liquid) introduced by means of conduit 414 andused to entrain and transport the particulate material through conduit414 is typically removed from vessel 412 via the one or more outletconduits 416. Conduits 416 may be positioned anywhere in vessel 412above the expected level 428 of particulate material collected. As shownin FIG. 5, outlet 416 may typically be positioned toward the closed top420 of vessel 412.

Due to the nature of the transport and the impact of particulatematerial in aspects of the invention, it is possible that least somefine particulate material will be generated in vessel 412. For example,in the processing of mortar from sand and cement, fine cement particlesare typically generated in vessel 412, for example, due to impact of thematerial against impaction plate 444. In order to minimize the escape offine entrained particles with the fluid stream discharged from outlet416, according to one aspect of the invention, at least some form ofparticulate filtering medium or collection system may typically beprovided. As shown in FIG. 5, according to one aspect of the invention,apparatus 400 may include at least one filter bag 452 adapted to collectfine particulate material generated while allowing the passage of fluid(again, typically air) to prevent the particulate material fromdischarging with the fluid discharged from outlet 416. According to oneaspect, a plurality of filter bags 452 may be suspended in vessel 412.The filter bags 452 may be mounted in vessel 412 by conventional means,for example, bags 452 may be mounted on support cables 454 suspended invessel 412. The filter bags 452 may be conventional filter bags, forexample, filter bags provided by STACLEAN Diffuser Company of Salisbury,N.C., or Gore-tex bags provided by W. L. Gore Corporation, or theirequivalent. In one aspect of the invention, the collection of filterbags mounted in apparatus 400 may be referred to as a “bag house”filtration system. In one aspect of the invention, the typically fineparticulate material accumulated on filter bags 452 may be returned tothe particulate mixture collected in bottom section 417, for example, byagitation or back flushing of filter bags 452. In another aspect, thetypically fine particulate material accumulated on filter bags 452 maybe isolated from the particulate mixture collected in bottom section 417and forwarded to further processing or disposal.

The handling and separation operation described with respect to FIGS.1-6 may be operated in “batch” or in “continuous” mode. In batch mode,after completion of a treatment or mixing “run” where the particulatematerials in apparatus 10, 110, 210, or 300 are depleted, theparticulate mixture in vessel 412 may be forwarded to furtherprocessing, for example, packaging or storage, or returned to apparatus10, 110, 210, or 300 for further processing. For example, theparticulate material in pile 428 in vessel 412 shown in FIG. 5 may betransferred to apparatus 10, 110, 210, or 300 via outlet conduit 418 andinlet conduits 33, 233, or 333 (see FIGS. 1-4) by opening isolationvalve 419, for example, a knife gate valve. In continuous mode, theparticulate material to be treated or mixed may be substantiallycontinuously introduced to apparatus 10, 110, 210, or 300, for example,by means of conduit 33, 233, or 333, respectively, and substantiallycontinuously removed from vessel 412 and forwarded to furtherprocessing, for example, via a conduit that communicates with outletconduit 418 in vessel 412.

FIG. 7 is a schematic diagram of a system 500 incorporating theapparatus 300 according to aspects of the present invention. System 500includes a feeding or treatment apparatus 510 comprising a vessel 512,an inlet chamber 513, a main fluid inlet 514, one or more supplementalfluid inlets 516, a fluid outlet 518, a draft tube 520, and aparticulate material inlet 522. As described above with respect toearlier aspects, apparatus 500 may comprise a handling, mixing,conveying, treatment and/or reaction system. For example, apparatus 500may be used to mix particulate material; to treat fluids introducedthrough inlets 514 and 516; to treat a first fluid, for example, a fluidintroduced to inlet 514, with a second fluid, for example, a fluidintroduced to inlets 516; to treat particulate material in vessel 512with one or more fluids via inlets 514 and 516; to react one or morefluids introduced via inlets 514 and 516; to react particulate materialin vessel 512 with one or more fluids introduced via inlets 514 and 516;to coat particulate material with one or more fluids introduced viainlets 514 and 516, among other functions.

Apparatus 510 may comprise one or more of the apparatus 10, 110, 210, or300 disclosed above. System 500 also includes a separation apparatus 530comprising a vessel 540 including particulate and fluid inlet 542 influid communication with draft tube 520, a fluid outlet 550, and aparticulate material outlet 560. As shown, tube 520 includes an inlet521 positioned in inlet chamber 513 and an outlet 523 positioned inapparatus 530. Apparatus 530 may comprise apparatus 400 shown in FIG. 5.

Though apparatus 530 is shown positioned vertically above and close toapparatus 510 in FIG. 7, apparatus 530 may be distal apparatus 530 anddraft tube 520 and fluid inlet 542 may comprise one or more transportconduits that effectively place apparatus 510 and apparatus 530 in fluidcommunication with each other. For example, apparatus 510 and apparatus530 may be connected by means of a rigid or a flexible transport linehaving bends or elbows and appropriate support hangers, as isconventional.

As shown in FIG. 7, system 500 includes at least one fluid supply 570operatively connected to inlets 514 and 516; numerous control andmonitoring devices (as will be discussed below); a control system 580adapted to control system 500 based, for example, upon user input, forinstance, via user interface (U/I) 584, and/or the parameters monitoredby the control and monitoring devices. Though aspects of the presentinvention are adapted to mixing mortars, for example, mortars comprisingsand and cement, system 500 in FIG. 7 may be used to mix or treat anyparticulate material, for example, any particulate material that can bepneumatically transferred. For example, the system shown in FIG. 7 maybe adapted to mix pharmaceuticals for blending active ingredients,blending active ingredients with excipients (that is, inert orsubstantially inert substances), blending excipients, food production,nutraceutical production (such as, for the production of dietarysupplements), ceramics processing, paint and pigment processing, thetreatment of fluids or particulate material as described above, or asneed in any field requiring the handling, conveying, treatment,reacting, or mixing of powders or particulates.

As shown in FIG. 7, main fluid inlet 514 and supplemental fluid inlets516 receive a flow of pressurized fluid, typically, air, from fluidsupply 570 through conduits 572 and 574, respectively. Fluid supply 570may comprise two or more fluid supplies providing two or more fluids toconduits 572 and 574, respectively, for example, two or more reactantsto be reacted in vessel 512. Fluid supply 570 typically includes someform of fluid pressurizing device, such as, a pump or blower (not shown)and conduits 572 and 574 typically include some form of fluid flowcontrol devices, such as, automated control valves 573 and 575,respectively. The one or more inlets 516 may comprise 3, 4, or moreinlets evenly spaced about the inlet chamber 513 of vessel 512. In oneaspect, inlets 516 may also vary in elevation about inlet chamber 513,for example, in a regular pattern.

As shown, inlet conduit 542 includes an open end 523 positioned withinvessel 540. Inlet conduit 542 may comprise an extension of tube 520.Outlet conduit 560 may typically include a valve 562, for example, anisolation knife gate valve, though a standpipe which allows solids topass downward and fluids to pass upward may also be used. Vessel 540 maycomprise multiple sections, for example, an upper or top section 541comprising a cylindrical vessel, for example, a circular cylindricalvessel, having closed top 544 and an open bottom 546. Vessel 540 mayalso include a lower or bottom section 548 having an open top mounted orconnected to open bottom 546 of section 541. Bottom section 548 maycomprise a downwardly converging bottom section, for example, having aninverted frusto-conical shape. The frusto-conical shape of section 548may have an axis concentric with the axis of upper section 541, or, asshown in FIG. 7, may have an axis that is off set from the axis of uppersection 541, for example, whereby section 548 converges to outlet 560 toone side of apparatus 530. Vessel 540 may also have other appropriateshapes.

As shown in FIG. 7, apparatus 530 may include an impaction plate 555positioned above open end 523 of conduit 542, for example, an impactionplate similar to plate 444 shown in FIGS. 5 and 6. As describedpreviously, impaction plate 555 provides a surface upon which theparticulate material discharged from conduit 542 impacts whereby clumpsof particulate material, if present, are disrupted and the particulatematerial may be deflected toward the closed bottom section 548 of vessel540. Impaction plate 555 may be mounted within apparatus 530 byconventional means. As shown in FIG. 7, impaction plate 555 may becentrally mounted by a mounting rod 557 suspended from the closed top544 of vessel 540. As also shown in FIG. 7, impaction plate 555 andmounting rod 557 may be mounted within conduit 559, which may also besuspended from closed top 544.

According to one aspect of the invention, the fluid flow F₃ from outlet518 may provide a means of regulating the pressure in feeder 510. Forexample, in one aspect, the pressure drop, ΔP_(DT), measured from theinlet 521 to the outlet 523 of tube 520, may provide a measure of theforce available to support the fluid-solid suspension flowing in tube520. The pressure drop that the fluid, typically, air, experiencesflowing across filter bags 561 may typically be small, whereby thepressure, P_(i), at the inlet 521 of tube 530 may define the pressuregradient, ΔP_(DT) that is available to accelerate and support the solidsand overcome both fluid-wall and solids-wall friction. The solidfraction flowing in tube 520 is typically the major contributor to thepressure gradient in both dilute and dense phase flows. Therefore, thesolids concentration in tube 520 typically requires establishing apressure gradient, ΔP_(DT), across tube 520 by manipulating,controlling, or otherwise regulating the pressures at the inlet 521and/or outlet 523 of tube 520, for example, by restricting the flowthrough tube 520, for instance, by restriction 21 (see FIG. 1), or theflow of fluid downstream of tube 520, for instance, by manipulatingvalve 552.

Control system 580 is adapted to control the operation of system 500based on user input and/or detected operating parameters. The operationof system 500 may be monitored and controlled automatically by controlsystem 580. Control system 580 may include main controlling device 582and user interface (U/I) 584, for example, a keyboard, mouse, or touchscreen, as is conventional. Controlling device 582 may a dedicatedpersonal computer or a dedicated control system, for example, having PLCcontrollers having PID control algorithms adapted to monitor and controlthe operation of system 500 based upon the particulate material beinghandled and the desired handling, mixing, or treatment.

In one aspect of the invention, at least two parameters (typically, atleast three parameters) may be regulated and controlled by controlsystem 580. For example, control system 580 may control the flow offluid through conduits 572 and 574 to inlets 514 and 516, respectively.As shown in FIG. 7, the flow of fluid through conduit 572 may beregulated and controlled by flow control valve 573 and the flow of fluidthrough conduit 574 may be regulated and controlled by flow controlvalve 575. Conduits 572 and 574 may include flow-measuring devices, suchas flow meters or DP cells (not shown). The measured parameters andcontrol signals to and from valves 573 and 575 and the flow measurementdevices may communicate with control system 580 via electricalconnections 560 and 561, for example, a 4-20 mA signal or a 0-1 VDC, 0-5VDC, or 0-10 VDC signal. The flow of fluid from outlet 518 may also beregulated and controlled by control system 580 by means of control valve527 and/or flow measuring device 529 via electrical connections 564 and531, respectively.

As shown in FIG. 7, vessel 512 may include at least one pressuredetector or sensor 566, the signal for which may be transmitted tocontrol system 580 via electrical connection 568. According to aspectsof the invention, pressure sensors 566 provide a pressure indication invessel 512, and a pressure indicative of the pressure at the inlet 521of conduit 520 to be used in providing an indication of the pressuredrop across conduit 520. Pressure sensor 566 may be located anywhere invessel 512, but preferably is located as close to inlet 521 as possible.As shown in FIG. 7, in one aspect, outlet conduit 550 of vessel 540 mayinclude a pressure-regulating device 552, for example, a control valve.Pressure regulating device 552 may provide a means for regulating andcontrolling the pressure in vessel 540. As shown, a pressure indicator566 may be located upstream of device 552 and communicate with controlsystem 580 via electrical connection 569. According to aspects of theinvention, by regulating and controlling the pressure in vessel 540, andthus the pressure at the outlet 523 of conduit 520, with knowledge ofthe pressure at the inlet of conduit 520 (for example, as indicated bypressure sensor 566), the pressure drop across conduit 520 may beregulated and controlled. Again, according to aspects of the invention,the regulating and control of this pressure drop across conduit 520,allows the operator to regulate and control the flow regime throughconduit 520, for example, dense or dilute phase flow, as well as, solidsmass flow rate and solids fraction. A pressure sensor 567 may also bepositioned anywhere on vessel 540 to indicate the pressure in thevessel, and communicate with control system 580 via electricalconnection 571.

System 500 shown in FIG. 7 may also be adapted to function as a reactorfor reacting the particulate material with a fluid, for example, withthe constituents of a fluid. Though system 500 may be adapted to manytypes of reagents and fluids, the following description of the treatmentof waste water with a photocatalyst is presented as one exemplaryreaction that may provided in system 500. According to one aspect of theinvention, vessel 512 may contain photocatalyst particles, that is, acatalyst that is activated by ultraviolet (UV) light, for example, atitanium dioxide (TiO₂) photocatalyst particles or pellets. As istypical of such catalysts, when activated (understood to mean when anelectron “hole” is generated), the TiO₂ pellet is imbued with anaffinity for negative ions (to fill that “hole”). In one aspect, wastewater, for example, filtered waste water, may be introduced to inlets516 in vessel 512 and allowed to flow upward through the activatedphotocatalyst pellets. In this application of system 500, inlets 516 arepreferably positioned distal inlet 514 (for example, as shown in FIG. 3)to minimize or prevent mixing of the waste water with the clean waterintroduced to inlet 514. In this case, due to its affinity for negativeions, the activated TiO₂ photocatalyst attracts a hydroxyl ion (OH⁻)producing a hydroxyl radical (OH.). The hydroxyl radical is thenavailable to oxidize constituents of the waste water, for example,organic material, such as pathogens, though inorganic material may alsobe beneficially oxidized. According to this aspect of the invention, asthe waste water passes upward through the catalyst bed, typicallywithout mixing of the bed, the catalyst pellets pass downward in acounter-current fashion toward the inlet 521 of conduit 520. As thewastewater rises through the catalyst pellets, the waste water isexposed to hydroxyl radicals, the wastewater constituents are oxidizedand the activity of the catalyst is reduced. By the time the waste waterreaches the top of the catalyst bed, the waste water may besubstantially completely oxidized where the oxidized waste water can bedischarged from outlet 518 and forwarded to storage; reuse, for example,as a source of water to inlet 514; or further treatment, for example, inanother oxidation system 500.

At the same time, as the down flowing catalyst reaches the inlet 521 ofconduit 520, the catalyst's activity may typically be reduced ordepleted entirely. The “spent” catalyst may then be transferred throughconduit 520, in a fashion typical of aspect of this invention, by theintroduction of, for example, relatively clean water into inlet 514. Thespent catalyst may, for example, be conveyed to a UV source toregenerate the catalyst. The UV source may be located in conduit 520, invessel 540, in a conduit between vessels 540 and 512, or at a remotelocation. In one aspect, vessel 540, with or without impaction plate555, may assist in separating the catalyst from the fluid, for example,by acting as a settling tank. After, UV regeneration, the activatedcatalyst may be reintroduced to inlet 522 and returned to vessel 512 totreat further waste water. Again, though waste water oxidation isdescribed as one reaction that may be performed in system 500, it willbe apparent to those of skill in the art that other similar or relatedreactions, for example, those that may benefit from the counter-currenttreatment and/or isolation of fluids that characterize aspects of theinvention, may also be implemented in system 500.

According to one aspect of the invention, the appropriate control of theoperation of system 500 permits a wide range of particle velocities andconcentrations (that is, solids fractions) in tube 520. For example,appropriate control of the operation of system 500 allows for differentregimes of flow to exist in tube 520 that can be exploited depending onthe materials being handled, mixed, and/or treated. The followingdescription explains how the operating variables may determine thesolids and gas flow rates, solids loading, and particle concentration intube 520 according to aspects of the invention.

According to one aspect of the invention, at least four variables may bemanipulated and controlled to establish a desired flow regime in tube520. These include the following fluid flows: the fluid jet flow, F₁, tothe bottom of the feeder 510 into inlet 514; the auxiliary fluid flow,F₂, to the inlet chamber 513 via inlets 516; the fluid flow, F₃ thatpasses from the inlet chamber 513, through the particulate material, andout of outlet 518; and the pressure drop, ΔP_(D), across the draft tube520. The fluid flow in tube 520, F_(t), may be determined by a massbalance of the fluid flows into and out of feeder 510, for example, byEquation 1.F _(t) =F ₁ +F ₂ −F ₃  Equation 1

According to one aspect of the invention, the fluid flow F₃ from outlet518 may provide a means of regulating the pressure in feeder 510. Forexample, in one aspect, the pressure drop, ΔP_(D), measured from theinlet 521 to the outlet 523 of tube 520, may provide a measure of theforce available to support the fluid-solid suspension flowing in tube520. The pressure drop that the fluid, typically, air, experiencesflowing across filter bags 561 may typically be small, whereby thepressure, P_(i), at the inlet 521 of tube 530 may define the pressuredrop, ΔP_(D), that is available to accelerate and support the solids andovercome both fluid-wall and solids-wall friction. The solid fractionflowing in tube 520 is typically the major contributor to the pressuredrop in both dilute and dense phase flows. Therefore, the solidsconcentration in tube 520 typically requires establishing a pressuredrop, ΔP_(D), across tube 520 by manipulating, controlling, or otherwiseregulating the pressures at the inlet 521 and/or outlet 523 of tube 520.For example, the pressure drop across tube 520 may be regulated orcontrolled by restricting the flow through tube 520; by restricting theflow of fluid downstream of tube 520, for instance, by manipulatingvalve 552; by introducing an under pressure, for example, asub-atmospheric pressure or vacuum in vessel 540; by introducing anoverpressure to vessel 540, for example, by introducing a fluid tovessel 540; or by a combination thereof.

The solid concentration flowing in tube 520 may also be affected by thedistance, L_(t), between inlet 521 of tube 520 and the outlet of inletconduit 514 of apparatus 510, that is, the distance 321 shown in FIG. 4.In one aspect, the solids concentration in tube 520 may be a strongfunction of L_(t). However, even when the distance L_(t) is large, thepressure at the inlet 521 of tube 520 may determine whether the flow inconduit 520 can be supported.

Another flow variable that may be controlled in one aspect of theinvention is the particle velocity, V_(p), of particles through tube520. In one aspect, the means for controlling the particle velocity,V_(p), is by controlling the fluid flow F₁, for example, when most ofthe fluid introduced to inlet 514 passes into and through tube 520.However, according to one aspect of the invention, there are a varietyof flow conditions that can be achieved using the system 500 shown inFIG. 7, for example, by setting the fluid flow through tube 520.Ultimately, the solid concentration in the conduit 520 is determined bythe pressure drop imposed across conduit 520. Some of these flowconditions are summarized in Table 1 below.

TABLE 1 Examples of Flow Regimes of the Invention Value of systemvariables Flow ΔP Property L_(t) F₁ F₂ F₃ (feeder) Low solids Low HighLow Low Low fraction, (to insure the jet air High particle primarilymoves up the velocity draft tube) Low solids Low Low Low Higher thanabove to Low fraction, insure any flow through low particle F₂ is notdiverted velocity into the draft tube. High solids High* High High LowHigh fraction, high particle velocity High solids High* Low High Higherthan above to High fraction, insure any flow though low particle F₂ isnot diverted velocity into the draft tube. *but less than the maximumspoutable height.According to one aspect of the invention, the flow F₃ may be such thatthe fluid velocity produced is less than the minimum fluidizationvelocity in the annulus about conduit 520 in inlet chamber 513, forexample, to minimize or prevent undesired disruption of the particulatematerial in this annulus. It will be understood by those in the art thatthe flow through tube 520, that is, F_(t), must typically be such thatthe fluid velocity produced in tube 520 is greater than the minimumfluid velocity required to transport the particulate material throughtube 520.

In one aspect of the invention, a typical control scheme for operatingsystem 500 may comprise the flow of fluid through inlet flow controlvalves 573 (also known as CV₁) and 575 (CV₂), through outlet flowcontrol valve 527 (CV₃), and the pressure drop ΔP_(D) across conduit 520in FIG. 7. As is typically in the art, each of control valves 573, 575,and 527 may be actuated independently. For given flows through valves573 and 575, the system may produce a solid and fluid flow rate throughtube 520, that is, F_(t), that is determined in part by the resistanceof flow through annular inlet chamber 513. For example, the morematerial there is in inlet chamber 513, the greater will be the pressuredrop ΔP_(D) across the tube 520. To increase the solid flow through tube520, increasing the flow F₂ and maintaining the flow F₃ will producehigher pressure inside of apparatus 510 whereby a higher flow throughtube 520 will be provided. Likewise, for given flows F₁ and F₃,decreasing F₂ will also decrease the amount of solid being transportedthrough tube 520. The pressure drop ΔP_(D) may be regulated andcontrolled by varying the pressure at the inlet 521 or the outlet 523.The pressure the inlet 521 is typically dictated by the flows F₁, F₂,and F₃ while the pressure at the outlet is typically dictated bypressure control device 552. In one aspect, by manipulating one or moreof these flow rates and/or the pressure control device 552 the flowregime through conduit 520, as well as, the solids mass flow rate andthe solids fraction, can be regulated and controlled as desired.

In one aspect of the invention, one or more of the following values maybe monitored and controlled: the mass flow through valve 573 (CV₁), thatis, F₁; the mass flow through valve 575 (CV₂), that is, F₂; the massflow through valve 527 (CV₃), that is, F₃; the pressure drop acrossdraft tube 520, ΔP_(D); the distance (or clearance) between the end ofinlet conduit 514 and the end 521 of tube 520 (L_(t)); or combinationsthereof. For example, the operation of system 500 may be regulated bycontrolling the flow through tube 520, that is, F_(t), by controllingthe flow of fluid through each of valves 573, 575, and 527, for example,to adhere to the mass flow relationship defined in Equation 1. Inanother aspect of the invention, flow through valves 573 and 575, thatis, F₁ and F₂, may be held substantially constant, and ΔP_(D) may becontrolled by regulating the flow F₃ from conduit 518 and/or by pressurecontrol device 552. In another aspect, the pressure detected by sensor566 in outlet 550 may be regulated by control device 552. Those of skillin the art will recognize that these are simply two of the many controlregimes that may be used for aspects of the invention.

According to one aspect of the invention, operation of the system 500may comprise first setting the draft tube spacing, L_(t), and thenregulating the flow of fluid mass though valves 573 (F₁) and valve 575(F₂) and setting pressure control device 552 to provide the transport ofparticles through tube 520 in a desired regime, for example, a densephase turbulent flow. The annulus air flow though valve 575 (F₂) may beadjusted to set the desired solids fraction in the tube 520 and the flowthrough valve 573, that is, the “jet flow,” (F₁) may be used todetermine the particle velocity in tube 520. In one aspect, a solidsmass flow rates up to 0.76 kg/s flowed through a 28.45 mm tube 520 (299kg/m² s) was achieved. The solids mass flow rate in tube 520 can bevaried by changing the draft tube spacing, L_(t), the flow to throughinlets 516 (that is, the aeration of the annulus”), the flow throughinlet 514 (that is, the “jet flow rate”), flow through outlet 518, orthe pressure via pressure control device 552. Table 2 presents typicaloperating parameters for the apparatus 500 according to aspect of theinvention, specifically, when the invention was used to coat 1 mmaerogel beads.

TABLE 2 Typical Operating Parameters of the System Shown in FIG. 7Parameter Value Notes Solids fraction, (1 − ε_(d)) 1% be weight ε_(d) =Voidage; specified Q₁ + Q₂ 767.5 L/min Specified; where Q_(n) isvolumetric flow rate and F_(n) is a mass flow rate; thus, F_(n) = ρQ_(n)Q_(SPRAY) 58.0 L/min Flow of spray coating to inlet; specified Q₃ 27.5L/min Calculated from Equation 1 Inside diameter of draft tube 520,D_(d) 41.15 mm Specified Outside diameter of draft 44.45 mm Specifiedtube 520, D_(o) Inside diameter of vessel, D 149.1 mm Specified Inletspacing, L_(t) 25.4 mm See 321 in FIG. 4; specified Particle Diameter 1mm Aerogel particles; specified Particle Density 140 kg/m³ SpecifiedHeight of particulate 0.526 meters Specified material, H_(a) AnnulusVoidage 0.42 Specified Length of draft tube 520, L_(d) 2 metersSpecified Pressure Drop across draft 96.2 Pascals A function of U_(d)and (1 − ε_(d)) tube 520, ΔP_(d) Pressure Drop across 265.7 PascalsAssuming a packed bed. annulus, ΔP_(a) Flow through draft tube 798.0L/min 520, Q_(t) Fluid velocity in draft tube 10 m/s 520, U_(d)

Examination of the operating parameters listed in Table 2 identifies atleast one limitations of prior art devices, for example, the device ofPlawsky, et al. (2003), in comparison to aspects of the presentinvention. According to aspects of the invention, the pressure at theinlet of the draft tube, and thus the pressure drop across the drafttube, is not a function of the draft tube flow velocity, Ud, but of theflow of fluid out of outlet 518, that is, F₃. According to the presentinvention, the pressure drop across the draft tube 520, that is, ΔP_(D),can be decreased to about 96.2 Pa, independent of the pressure dropacross the annulus. This can be achieved according to aspects of theinvention by regulating the flow out of the vessel through valve 527,that is, F₃ or by regulating the pressure in vessel 540 via pressurecontrol device 552. However, in order to achieve this low pressure inthe prior art device of Plawsky, et al. (2003), the particulate materialheight H_(a) would have to be reduced to impractical levels, forexample, H_(a) would have to be about 0.133 meters, that is, about 5inches, a height that would be difficult to maintain while maintainingthe proper operation of the draft tube. Aspects of the present inventionovercome this problem by not requiring the pressure drop across thedraft tube to be equal to the pressure drop across the particulatematerial in the annulus about tube 520.

FIG. 8 is a schematic diagram of a particle mixing system 600 having aplurality of particulate feeders 610 and 620 and a collection vessel 630according to another aspect of the invention. Feeders 610 and 620 may besimilar to apparatus 10, 110, 300, and 510 described above. Vessel 630may be similar to apparatus 400 and 530 described above. According tothis aspect of the invention, the plurality of feeders 610 and 620 (ormore) include tubes 640 and 650, respectively, that are directed intocommon vessel 630 whereby the fluid streams discharged by tubes 640 and650 are directed against each other to enhance mixing and the disruptionof clumps. In one aspect, the streams may be directed against a commonsurface, for example, upon the opposite sides of a common plate. In oneaspect, system 600 may also be used as a particle grinder to grindparticles to finer sizes as needed.

According to aspects of the present invention, a new and improveddraft-tube, spout-fluid bed handling apparatus, mixing apparatus,treating apparatus, and/or reactor is provided for particulate material.The treating apparatus and reactor provide novel means of processingreagents in a counter-current fashion that enhances efficacy whileminimizing the undesirable mixing of reagents. The mixing aspect of theinvention provides improved uniformity of product that characterize highshear rotary mixing while providing improved dispersion of the mixedcomponents. With such improved mixing and dispersion of particlesimproved mixtures, for example, improved mortars of acceptablecompressive strength and improved pharmaceuticals can be produced.Aspects of the invention also provide an improved reactor and method ofreacting and treating particulate material, for example, forpetrochemical processing and biochemical processing.

While several aspects of the present invention have been described anddepicted herein, alternative aspects may be effected by those skilled inthe art to accomplish the same objectives. Accordingly, it is intendedby the appended claims to cover all such alternative aspects as fallwithin the true spirit and scope of the invention.

1. A particulate material handling apparatus comprising: a vessel havinga top and a bottom; a vertically extending conduit having an inlet inthe vessel and an outlet; a fluid inlet in the bottom of the vessel, thefluid inlet directed toward the inlet of the vertically extendingconduit wherein a pressurized fluid introduced there through produces aflow of at least some particulate material from the vessel and fluidthrough the vertically extending conduit; a fluid outlet from thevessel; and a control system that regulates flow of fluid through thefluid inlet, flow of fluid through the fluid outlet, and pressure dropacross at least a portion of the vertically extending conduit toindependently control particle velocity and solids fraction of flowthrough the vertically extending conduit.
 2. The apparatus as recited inclaim 1, wherein the control system regulates at least one restrictionpositioned in one of the vertically extending conduit and down stream ofthe vertically extending conduit.
 3. The apparatus as recited in claim1, wherein the fluid inlet comprises a first fluid inlet, and whereinthe device further comprises at least one second fluid inlet.
 4. Theapparatus as recited in claim 3, wherein the at least one second fluidinlet comprises a fluid reactant inlet operatively connected to a sourceof fluid reactant that reacts with at least some of the particulatematerial.
 5. The apparatus as recited in claim 1, wherein the fluidinlet in the bottom of the vessel produces a flow of a plurality ofparticulate materials from the vessel through the vertically extendingconduit to mix the plurality of particulate materials.
 6. The apparatusas recited in claim 5, wherein the plurality of particulate materials tobe mixed comprise sand and cement.
 7. The apparatus as recited in claim1, wherein the fluid inlet comprises a fluid reactant inlet operativelyconnected to a source of fluid reactant that reacts with at least someof the particulate material.
 8. The apparatus as recited in claim 7,wherein the fluid reactant reacts with at least some of the particulatematerial flowing through the vertically extending conduit.
 9. Theapparatus as recited in claim 1, wherein the fluid inlet comprises atreatment fluid inlet operatively connected to a source of treatmentfluid that treats at least some of the particulate material.
 10. Theapparatus as recited in claim 1, wherein the bottom of the vesselcomprises a conical head having an apex and converging sides, andwherein the fluid inlet is positioned at the apex of the conical head.11. The apparatus as recited in claim 10, wherein the fluid inletpositioned at the apex of the conical head comprises a first fluidinlet, and wherein the apparatus further comprises at least one secondfluid inlet directed through the converging sides of the conical head.12. The apparatus as recited in claim 1, wherein the vessel comprises afirst vessel, and wherein the apparatus further comprises a secondvessel positioned to receive the flow of particulate material and fluidfrom the vertically extending conduit, the second vessel having a topand a bottom.
 13. The apparatus as recited in claim 12, wherein theapparatus further comprises a conduit for transferring particulatematerial from the second vessel to the first vessel.
 14. The apparatusas recited in claim 12, wherein the apparatus further comprises animpaction surface located in the second vessel and positioned to beimpinged by the flow of particulate material and fluid from thevertically extending conduit to promote mixing of the particulatematerial.
 15. The apparatus as recited in claim 14, wherein the meansfor collecting at least some of the fine particulate material comprisesa filtering medium.
 16. The apparatus as recited in claim 15, whereinthe filtering medium comprises at least one bag filter positioned in thesecond vessel.
 17. The apparatus as recited in claim 12, wherein atleast some fine particulate material is produced in the second vessel,and wherein the device further comprises means for collecting at leastsome of the fine particulate material.
 18. The apparatus as recited inclaim 1, wherein the control system further regulates fluid flowvelocity through the vertically extending conduit.
 19. The apparatus asrecited in claim 1, wherein the fluid inlet comprises a coating fluidinlet operatively connected to a source of coating fluid that coats atleast some of the particulate material.
 20. The apparatus as recited inclaim 19, wherein the particulate material comprises an aerogel.
 21. Theapparatus as recited in claim 1, wherein the vertically extendingconduit and the vessel provide an annular region between the outside ofthe conduit and the inside of the vessel, wherein the particulatematerial is positioned in the annular region.
 22. The apparatus asrecited in claim 21, wherein the pressurized fluid introduced throughthe fluid inlet produces a flow of at least some of fluid upward throughthe particulate material in the annular region.
 23. The apparatus asrecited in claim 22, wherein the control system further regulates upwardflow of fluid through the particulate material in the annular region.24. The apparatus as recited in claim 23, wherein the control systemregulates a flow control valve positioned in a flow outlet of thevessel.
 25. The apparatus as recited in claim 21, wherein thepressurized fluid introduced through the fluid inlet comprises areactant adapted to react with the particulate material in the annularregion.
 26. The apparatus as recited in claim 1, wherein the controlsystem independently varies particle velocity and solids fraction offlow through the vertically extending conduit.